Doctors aim to save gunshot victims by freezing them in ‘suspended animation’

Researchers in Pennsylvania are testing a new technique to freeze gunshot victims in suspended animation, keeping them hovering between life and death, while doctors try to save their lives. The first human trials began in May.

The groundbreaking approach of suspended animation is actually
called emergency preservation and resuscitation (EPR). “We
are suspending life, but we don't like to call it suspended
animation because it sounds like science fiction," Samuel
Tisherman, a surgeon at the University of Pittsburgh Medical
Center (UPMC) Presbyterian Hospital, who is leading the trial,
told
New Scientist.

Unlike in science fiction, this state of suspended animation
isn’t designed to preserve life for decades into the future, like
with TV show Futurama’s head jars or baseball star Ted Williams’
cryogenically frozen head and body. Instead, the doctors will
freeze the gunshot victims’ bodies to “buy time” for transport
and resuscitative surgery, the University of Pittsburgh said.

Tisherman’s team will do their research on patients who have
suffered cardiac arrest after a traumatic injury resulting in
blood loss and who are unresponsive to attempts to restart their
hearts, New Scientist reported. “The patient will probably
have already lost about 50 per cent of their blood and their
chest will be open," Tisherman said. Their survivability
rate at this point is less than 7 percent.

The doctors will quickly induce hypothermia, freezing the
patient’s internal organs by removing all the blood from the body
and flushing the system with a cold saline solution through the
heart and into the brain, cooling the body down to 10 degrees
Celsius. “At this point they will have no blood in their
body, no breathing, and no brain activity. They will be
clinically dead,” New Scientist reported.

Normally, when the heart stops beating, oxygen stops flowing to
the brain and the brain dies after five minutes with no oxygen.
But cells need less oxygen the colder they are, so the
hypothermia preserves the victim’s life by slowing down the
chemical reactions inside the body and preventing the brain from
realizing it hasn’t received oxygen. Doctors will then have
several hours to repair the trauma from the gunshot before
resuscitating the patient.

The technique was developed by Dr. Peter Rhee, who successfully
tested it on pigs in 2000, CNET reported. Rhee’s test required
cutting the pigs’ arteries with scalpels and replacing their
blood with saline to drop their body temperatures to 10 degrees
Celsius, while leaving the body temperatures of a control group
of pigs alone. All of the pigs in the control group died, but 90
percent of the EPR pigs survived.
CNET noted that some of the pigs in the trial did have to be
“given a jump start,” but that after the trial, “the
pigs demonstrated no physical or cognitive impairment.”

Scientists in Boston followed up on Rhee’s research in 2006,
using hydrogen sulphide gas to induce hypothermia in mice,
BBC
News reported at the time. Researchers found that the mice’s
heart rates and respiration fell as their body temperatures fell,
but their heart rates did not fall, “which tends to happen
with other techniques such as lowering body temperature.”
The effects of the gas on the mice “seemed to be
reversible,” with the mice’s vital signs returning to normal
within two hours after removing the gas.

"After we did those experiments, the definition of 'dead'
changed," Rhee told New Scientist. "Every day at work I
declare people dead. They have no signs of life, no heartbeat, no
brain activity. I sign a piece of paper knowing in my heart that
they are not actually dead. I could, right then and there,
suspend them. But I have to put them in a body bag. It's
frustrating to know there's a solution."

Tisherman and the doctors on his team will perform their research
in hospital emergency rooms at the University of Pittsburgh and
the University of Maryland, and will not be able to gain consent
from their subjects. However, the study will use the US Food and
Drug Administration’s “exception-from-informed-consent
process,” according to New Scientist, which required the
team to hold meetings with community groups, advertise in local
newspapers and create an online opt-out form. So far, no one has
elected to opt out in advance.

Once the team has tested the technique on 10 people, they will
compare their outcomes with the outcomes of a control group of 10
people who met the same criteria but did not receive the EPR
treatment. The doctors will refine the process, then test the
updated version on another 10 people, until there are enough
results to analyze, Tisherman told New Scientist.

"We've always assumed that you can't bring back the dead. But
it's a matter of when you pickle the cells," Rhee said to
New Scientist, which calls to mind the emergency room adage of
dealing with hypothermia: "You're not dead until you're warm
and dead."